Vaccinate animals, including horses, for rabies

A horse near Peetz, Colo., has been diagnosed as being positive for rabies by CSU Veterinary Diagnostic Laboratory.

The horse had been exhibiting neurological clinical signs, the attending veterinarian suspected rabies, euthanized the horse, and submitted samples for testing.

There has been a significant increase in the incidence of rabies over the last five years in Colorado. This rabies-positive equine case points out the need to consider rabies as a possible etiology in all neurological cases.

The predominant terrestrial animal which acts as a vector for rabies is the skunk, but other wildlife species that can carry and transmit the rabies virus are bats, raccoons and foxes.

There are many excellent rabies resources and rabid animal data on the Colorado Department of Public Health and Environment’s webpage at www.colorado.gov/cdphe/rabies.

Colorado Department of Agriculture Field Veterinarian Dr. Ken Newens stresses to veterinarians, “Using personal protection during the physical exam of horses is really important, especially around the mouth. With EHV-1 and rabies fairly common now, and with drought conditions making poisonous plant ingestion more likely down the road, keep a wide differential list when called to any neuro case in any species, but protect yourselves as if every case was rabies. Initially rabid horses can exhibit clinical signs of colic … so an open mind and good client communication is important on the initial exam.”

This recent case of rabies in a horse highlights the importance to inform and recommend that owners not only vaccinate their dogs and cats, but also other animals that could be exposed to wildlife that carry and transmit the rabies virus. This includes horses, small ruminants, llamas, alpacas, petting zoo animals and possibly other valuable livestock.

Many rabies cases that involve livestock result in numerous people having to take post exposure prophylaxis; this is also true in this latest rabies-positive horse.

Considering the current incidence of wildlife rabies, the lethal outcome of the disease, and the cost and liability when people have been exposed to a possibly rabid animal, the benefits of vaccinating animals for rabies certainly outweigh other potential reasons for not vaccinating for rabies.

The Compendium of Animal Rabies Prevention and Control 2011 recommends that “All horses should be vaccinated against rabies. Livestock, including species for which licensed vaccines are not available, that have frequent contact with humans (e.g., in petting zoos, fairs and other public exhibitions) should be vaccinated against rabies. Consideration should also be given to vaccinating livestock that are particularly valuable.” The Compendium also has a listing of approved vaccines for the different species and a recommended vaccination schedule, available at www.nasphv.org/Documents/RabiesCompendium.pdf.

For those species of animals in which there are no licensed vaccines, consult with practicing veterinarians or university veterinarians who have had experience in those particular species. Concerning the rabies vaccination of camelids, CSU Veterinary Extension has a fact sheet that addresses vaccine and appropriate dose; it can be found at http://veterinaryextension.colostate.edu/menu2/camelids/2010%20Rabies%20Poster%20CSU%20VTH.pdf.

Dr. Mary Smith at Cornell University recommends using IMRAB Large Animal at 2cc per head in species for which there is no licensed or labeled rabies vaccine because it is a killed product that is licensed and labeled for more large animal species than other rabies vaccines.